Variable eccentric for steam-engines



(No Model.)

M. C. BULLOCK.

' VARIABLE EGGENTEIG EOE STEAM ENGINES. No. 274,436. Patented Ma1.20,1883.

n mm. IWW. www n L UNITED STATES PATENT OFFICE.

MILAN C. BULLOCIL CF CHICAGO, ILLINOIS.

'VARlABLE ECCENTRIC FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 274,436, daten March 2o, ieee. Applicntipn filed February 19, 1883. (No modelli To all whom it may oon-cern Be it known that I, MILAN (LBULLooK, a citizen of the United States, residing at Chicago, in the county of Cook and State ot' Illinois, have invented certain new and useful Improvements in Variable Ecoentrics for Steam- Engines; and I do hereby declare the following to be a full, clear, and exact description ot' the invention, such as will enable others skilled in the art to which it appertains to makeand use the same. Y

The improvement hereinafter describedaud ciauned is part of my invention described in my application for Letters Patent filed June 24, A. D. 1881, and was separated therefrom in compliance with an order of the United States Patent Office, requiring a division of said application.

This part of my invention consists of a va riable and reversible eccentric for operating the valve or valves of steam-engines, the distinguishing novel features of which are stated concisely in the claims 'at the close of this specification.

In order that my invention may be clearly understood, I have illustrated in the annexed dravvin gs, and will proceed to describe, thebest form thereof at present known to me.

In the drawings, Figure 1 is a sectional elevaton,showing the eccentric and its adjuncts mounted upon the crank-shaft ot a steam-engine. Fig. 2 is a perspective view, partly in section, showing a portion of the crank-shaft with the variable eccentric and its shifting mechanism mounted thereon. Fig. Sis a transverse section, showing the shaft, the ribbed rotatin g sleeve, the tubular slide and its grooved bush. Fig. 4: is a section showing, in full lines,

the eccentric at one limit of its adjustment on the shaft, and in broken lines the opposite limit oi' adjustment, showing also the link for connecting the eccentric with the ribbed sleeve. Fig. 5 is a sectional viewillustrating one method of connecting the eccentric with the ribbed sleeve. Fig. 6 is a sectional view illustrating another method of connectin g these parts. Fig. 7 is a perspective view of the spirally-grooved bush.

The same letters of reference are used in all the figures in tbe designation of identical parts.

The illustrated eccentric A is provided witl1 twostraps, so as to adapt it for operating two -may be reversed by swinging the eccentric;

from one extreme position `to the opposite one.

By lesser adjustments ofthe eccentric the throw of the valves may be readily adjusted. The eccentric A, thus pivoted, is connected by a link, a', to an arm on the adjacent end of a sleeve, C, which is so fitted upon the crankshaft that it may be rotated, but cannot be moved endwise thereon or, instead of connecting the eccentric and rotating sleeve by means of the link aggear-teeth may be formed at the end of said sleeve to engage a segmental rack formed on or connected to the face of the eccentric, as shown in Fig. 6. This sleeve C is constructed with spiral ribs or threads c on its surface, and is encircled by a bush, D', in which spiral grooves d' are ont to engage the spiral threads on the sleeve. Itis apparent that this construction may bemodiiied by forming the grooves in the sleeve C and providing the bush D with spiral ribs or threads; or one of the members C or D' may be provided with pins or studs, either fixed or removable, to engage the spiral grooves of the other member. The bush D is fixedin the split end of a tubular slide, D,so as to form part thereof, but the bush may be dispensed with, and the tubular slide mayitself be provided with either grooves or ribs to engage the grooves or ribs ofthe rotatin g sleeve C. The other and contracted end of the tubular slide is connected by feather and groove to the crank-shaft,-with which it turns, but on which it may be slid endwise. Thus the hushed tubular slide will iirmly hold the rotating sleeve, and through it the eccentric. It will be observed, however, that by sliding the tubular slide on the crank-shaft its spirally-grooved bush will turn the spirallythreaded sleeve, which will in turn, through the medium of its connection with the eccentric, swing the latter on its pivot. The tubular slide is encircled at its contracted end by IOO ' a ring, D2, studs on which are engaged by the shifting or reversing lever E, by operating which the eccentric may be adjusted at pleasure. The split end of the tubular slidel is con-f structed with ears, so that the segments may be drawn together by bolts el, as shown in Figs. 2 and 3, and lost motion between the spiral threads and spiral grooves be readily taken up. Theslota of the eccentric is of sufcient Width to permit the eccentric to move freely, but not loosely, back and forth upon the crank-shaft, and it may have continuous walls, or be provided with offsets, so that it will move more freely upon the shaft when being shifted. The bush D', when used, is secured to the tubular slide by any suitable means-such, for instance, as the screws d2, shown in Fig. 3.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. The combination, substantially as before i set forth, of the slotted eccentric pivoted to an arm on the crank-shaft, the sleeve mounted to rotate on the crank-shaft for shifting the eccentric across the axis thereof, and the tubular slide feathered to the shaft and adapted to rotate the sleeve thereon.

2. The combination, substantially as before set forth, of the slotted eccentric pivoted to an arm on the crank-shaft, the sleeve linked to said eccentric, andV means for rotating said sleeve.

3. The combination, substantially as before set forth,of the slotted eccentric pivoted to an arm .on the crank-shaft, the spirallythreaded sleeve linked to said eccentric, and the tubular slide having` grooves to engage the spiral 

